Monday, January 21, 2019

Announcing Hosting for Oracle ADF Rich Client and Oracle ADF WorkBetter Demos

If you are curious about how Oracle ADF works or want to explore a rich set of ADF Faces components - welcome to access Oracle ADF demo apps hosted on our cloud server.

We launched a dedicated website Oracle ADF Components. Hosted demos:

1. ADF Faces Rich Client
2. ADF Work Better


These demo apps can be downloaded from Oracle, you could run them on your own environment too. But sometimes it is useful to have apps online for quick access.

Saturday, January 19, 2019

Oracle ADF BC Reusing SQL from Statement Cache

Oracle ADF BC by default is trying to reuse prepared SQL query from statement cache. It works this way when ADF BC runs with DB pooling off (jbo.doconnectionpooling=false). Normally we tune ADF application to run with DB pooling on (jbo.doconnectionpooling=true), this allows to release unused DB connection back to the pool when a request is completed (and in this case, statement cache will not be used anyway). If View Object is re-executed multiple times during the same request - in this situation, it will use statement cache too.

However, there are cases when for specific View Object you would want to turn off statement cache usage. There could be multiple reasons for this - for example, you are getting Closed Statement error after it tries to execute SQL for statement obtained from statement cache. Normally you would be fine using statement cache, but as I said - there are those special cases.

We are lucky because there is a way to override statement cache usage behavior. This can be done in View Object implementation class either for particular View Object or in the generic class.

After View Object was executed, check the log. If this is not the first execution, you will see log message - "reusing defined prepared statement". This means SQL will be reused from statement cache:


To control this behavior, override getPreparedStatement method:


We create new prepared statement in this method, instead of reusing one from the cache.

As a result - each time View Object is executed, there is no statement cache usage:


Download sample application from GitHub repo.

Saturday, January 12, 2019

On-Premise Machine Learning with XGBoost (Katana 19.1)

Happy to announce Katana 19.1 release with complete on-premise support for Machine Learning.



You can run Machine Learning (ML) models on Cloud (Amazon SageMaker, Google Cloud Machine Learning, etc.). I believe it is important to understand how to run Machine Learning in your own environment too. Without this knowledge ML skills set would not be complete. There are multiple reasons for this. Not everyone is using Cloud and you must provide on-premise solution. Without getting your hands dirty and configuring environment yourself, you would miss an exciting opportunity to learn more about ML.

Read more here.

Tuesday, January 8, 2019

Oracle Visual Builder 18.4.5 and JET 6 Support

Oracle Visual Builder 18.4.5 comes with very neat and polished UI. Also it brings Oracle JET 6 support (latest JET version to date). Read more about it - New Features in Oracle Visual Builder December Release.

I have upgraded our VBCS instance to 18.4.5:


I was curious how automatic upgrade would work for VBCS app implemented in the previous version (download source code for the upgraded app from my GitHub repo). Especially that now VBCS is using newer JET too. I must say I was pleased with the results - application was upgraded to JET 6 automatically without manual interference:


I did a quick check in the source on runtime - indeed our upgraded VBCS app is using JET 6:


Awesome work by VBCS team.

Thursday, December 27, 2018

Knockout.js - Updating Single Array Element (Oracle JET)

If you implement tables and using Knockout.js to push data updates from JS to HTML - probably you experience a situation when it doesn't work to push an update for one of the columns. I mean you could replace the whole observable array element - this would cause full row refresh. But visually this doesn't look nice and why to refresh the whole row, if only one (or few) element (-s) from the row must be refreshed.

If you need to refresh a specific array element (or row column in other words) - you must define the value of that column to be observable.

Refresh will be happening much more smooth, instead of refreshing whole row. See how fast Risk column value is changed after clicking on Process button:


Table is implemented with Oracle JET table component. JET table allows to define template slots, this helps to create a better structure for table columns implementation:


Risk column - the one which is being refreshed is defined as an observable variable in the array:


A new value for Risk column is set directly - by iterating array elements. Refresh on UI happens automatically, through Knockout observable:


Sample application source code is available on my GitHub repo.

Monday, December 24, 2018

Tweet Escalation to Your Support Team — Sentiment Analysis with Machine Learning

I have published an article on Towards Data Science. I explain end-to-end technical solution which would help to streamline your company support process. With the focus on airline support requests received from Twitter. It could save a lot of time and money for the support department if they would know in advance which request is more critical and must be handled with higher priority.

Read the full article here - Solution to automate tweet sentiment processing for airline support request escalation.


Sunday, December 23, 2018

Understanding Attributes Enum in ADF BC Row Class

Did you ever wonder why Attributes Enum is generated by JDeveloper in Entity or View Row class? Attributes Enum holds a collection of attribute names and there is a set of static variables with attribute indexes. These indexes are used to locate attribute in getter/setter. Attributes Enum is a structure which is required for JDeveloper on design time to generate Java code. On runtime Attributes Enum is needed only as long as you are using a static variable index in the getter/setter.

Attributes Enum and list of static indexes in View Row class:


Static index is used in the getter/setter to access attribute:


Attributes Enum is mimicking attributes order in the VO/EO. You can think about it as about attributes metadata. It is not mandatory to use index from Attributes Enum. In some use cases, you could get attribute index directly from VO/EO Def and use it to access attribute:


First name is fetched correctly using overridden getter:


Download sample code from GitHub